Molecular profiling has emerged as an important strategy for identifying marker "signatures" associated with the biological changes that characterize specific cancers. To realize the full potential of the wealth of new biomarker information, it is essential to develop strategies for profiling human tissue and tumor specimens that are workable in a clinical setting. Clinical specimens are heterogeneous, and tissue heterogeneity is one of the major sources of complexity that must be addressed in the application of molecular profiling to the analysis of human cancers. We have developed a set of novel "tissue print" techniques that allow us to profile the molecular markers over extended areas of human tissue and tumor samples without damaging the specimen. We first applied our new tissue print techniques in the profiling of protein markers associated with capsular invasion in radical prostatectomy specimens. More recently, we have discovered that, during tissue print collection, we can peel a layer of cells off of the specimen and that this process does not cause detectable tissue damage (as determined by surgical pathologists), and thus does not interfere with routine clinical surgical pathology. We have also shown that the cells collected in the tissue print "micropeel" are adequate for PCR and quantitative rt-PCR analysis, allowing us to score multiple molecular markers and assemble the results in "tiling patterns" corresponding to the specimen surface. In the project outlined in this proposal, we will work closely with the research and development team at Qiagen Inc. to optimize the yield of mRNA and DNA from our tissue print micropeels collected from human prostate and breast tissue/tumors specimens. We will then develop a proof-of-principle pilot application of the tissue-print micropeel sampling technique for prostate needle biopsies, one of the classes of specimens that must be conserved intact for clinical diagnosis. Our long term goal is to utilize tissue print techniques in the clinical setting to simplify the process of obtaining an adequate representation of human cancers in biopsies and surgical specimens, and to develop protocols for this tissue sampling platform to support both proteomic analysis and PCR-based DNA and mRNA profiling techniques. In addition to facilitating basic and translational research, the tissue-printing platform can also be utilized as a tool for dedicated clinical applications, to provide "molecular sections" of extended areas of the specimen when the marker profile is itself of potential diagnostic importance.